Turbine with bucket fixing means

Abstract

Provided is a turbine including a rotor wheel including a plurality of dovetail grooves and a insertion groove, the insertion groove including a first catching groove; a plurality of first buckets, each of the plurality of first buckets including a vane, a platform provided at a first end portion of the vane, and a dovetail provided at the platform and having a shape corresponding to the dovetail groove; a second bucket including a vane, a platform provided at a first end portion of the vane, and a protrusion portion and configured to be inserted into the insertion groove, the protrusion portion including a second catching groove; and a fixing member configured to be inserted into each of the first and second catching grooves, the fixing member configured to restrict radial movement of the second bucket.

What is claimed is: 
     
       1. A turbine comprising:
 a rotor wheel comprising a plurality of dovetail grooves and an insertion groove, the plurality of dovetail grooves and the insertion groove arranged in a circumferential direction of the rotor wheel, the insertion groove comprising at least one first catching groove provided on an inner surface of the insertion groove; 
 a plurality of first buckets, each of the plurality of first buckets comprising:
 a first vane; 
 a first platform provided at a first end portion of the first vane; and 
 a single dovetail provided at the first platform, the single dovetail having a first shape corresponding to a shape of a corresponding dovetail groove of the plurality of dovetail grooves; 
 
 a second bucket comprising:
 a second vane; 
 a second platform provided at a first end portion of the second vane; and 
 a single protrusion having a second shape different from the first shape of the dovetail, provided at the second platform and configured to be inserted into the insertion groove, the single protrusion comprising at least one second catching groove; and 
 
 a fixing member configured to be inserted into each of the at least one first catching groove and the at least one second catching groove, the fixing member configured to restrict radial movement of the second bucket, wherein 
 the insertion groove has a different shape from the plurality of dovetail grooves, the insertion groove comprising axial side walls that extend from an outermost radial surface of the rotor wheel to a bottommost surface of the insertion groove, the axial side walls being opposed to each other and inclined towards each other such that a circumferential distance between the axial side walls continuously decreases from the outermost radial surface of the rotor wheel to the bottommost surface of the insertion groove. 
 
     
     
       2. The turbine according to  claim 1 , wherein the at least one second catching groove comprises a plurality of second catching grooves, the plurality of second catching grooves are respectively provided on opposite sides of the single protrusion. 
     
     
       3. The turbine according to  claim 1 , wherein the single protrusion of the second bucket is configured to be radially inserted and coupled to the insertion groove. 
     
     
       4. The turbine according to  claim 1 , wherein the single protrusion comprises a side portion having a circumferential width decreasing as advancing toward a center of the rotor wheel. 
     
     
       5. The turbine according to  claim 2 , wherein the at least one first catching groove comprises a plurality of first catching grooves, and
 wherein the plurality of first and second catching grooves are radially spaced along sides of the single protrusion respectively. 
 
     
     
       6. The turbine according to  claim 2 , wherein the fixing member has a circular cross-sectional shape. 
     
     
       7. The turbine according to  claim 1 , wherein:
 the first bucket further comprises a first shroud which is integrally provided at a second end portion of the first vane; 
 the second bucket further comprises a second shroud which is integrally provided at a second end portion of the second vane; and 
 each of the first and second shrouds comprises: 
 a planar portion which is tangentially provided at an outer end portion of the first and second vanes; and 
 protrusion hooks radially protruding from opposite end portions of the planar portion, respectively. 
 
     
     
       8. The turbine according to  claim 7 , wherein each of the first and second shrouds comprises axial decoupling prevention portions circumferentially inclined from an axial end portion of the planar portion and
 wherein the protrusion hooks are arranged adjacent to the axial decoupling prevention portions. 
 
     
     
       9. The turbine according to  claim 7 , wherein each of the first and second platforms has a flat plate shape, and comprises axial decoupling prevention portions circumferentially inclined from opposite sides of an axial end portion of each of the first and second platforms. 
     
     
       10. The turbine according to  claim 1 , wherein each of opposite end portions of the fixing member comprises an axial decoupling prevention hook, the axial decoupling prevention hook configured to protrude circumferentially and radially. 
     
     
       11. The turbine according to  claim 10 , wherein the axial decoupling prevention hook comprises a rivet. 
     
     
       12. The turbine according to  claim 1 , wherein the at least one first catching groove and the at least one second catching groove have different depths from each other. 
     
     
       13. A turbine comprising:
 a rotor wheel comprising:
 a plurality of dovetail grooves; and 
 an insertion groove provided between the plurality of dovetail grooves; 
 
 a plurality of first buckets, each of the plurality of first buckets comprising a single dovetail configured to engage with a corresponding dovetail groove of the plurality of dovetail grooves, the single dovetail having a first shape corresponding to a shape of each of the plurality of dovetail grooves; 
 a second bucket comprising a single protrusion inserted into the insertion groove, the single protrusion having a second shape different from the first shape of the single dovetail; and 
 a fixing member configured to be inserted between the single protrusion and the insertion groove, the fixing member configured to restrict radial movement of the second bucket, wherein 
 the insertion groove has a different shape from the plurality of dovetail grooves, the insertion groove comprising axial side walls that extend from an outermost radial surface of the rotor wheel to a bottommost surface of the insertion groove, the axial side walls being opposed to each other and inclined towards each other such that a circumferential distance between the axial side walls continuously decreases from the outermost radial surface of the rotor wheel to the bottoms surface of the insertion groove. 
 
     
     
       14. The turbine according to  claim 13 , wherein the fixing member is inserted into each of at least one first catching groove concavely provided on the outer wall of the insertion groove and at least one second catching groove concavely provided on the outer wall of the single protrusion. 
     
     
       15. The turbine according to  claim 13 , wherein the fixing member has one of a circular cross-sectional shape, an oval cross-sectional shape, and a polygonal cross-sectional shape. 
     
     
       16. The turbine according to  claim 13 , wherein the fixing member comprises a plurality of fixing members, the plurality of fixing members inserted into each of opposite sides of the single protrusion. 
     
     
       17. The turbine according to  claim 14 , wherein a circumferential distance between first catching grooves provided on opposite surfaces of the insertion groove and facing each other provided within the insertion groove is decreased as advancing toward a center of the rotor wheel. 
     
     
       18. The turbine according to  claim 13 , wherein each of the first and second buckets further comprises a shroud which is integrally formed at one end portion thereof. 
     
     
       19. The turbine according to  claim 13 , wherein each of opposite end portions of the fixing member comprises a deformation portion, and
 wherein the deformation portion protrudes from a side of the rotor wheel and configured to be mechanically deformed. 
 
     
     
       20. The turbine according to  claim 19 , wherein the deformation portion comprises a radially expanded portion. 
     
     
       21. The turbine according to  claim 1 , wherein the second bucket is configured to inserted into the rotor wheel in a radial direction of the rotor wheel, and
 the plurality of first buckets are configured to be inserted into the rotor wheel in an axial direction of the rotor wheel. 
 
     
     
       22. The turbine according to  claim 13 , wherein the second bucket is configured to inserted into the rotor wheel in a radial direction of the rotor wheel, and
 the plurality of first buckets are configured to be inserted into the rotor wheel in an axial direction of the rotor wheel.